Sustainability Talk: Timber Trends

This month’s Cullinan Studio Sustainability Talk ‘Timber Trends’ was introduced by the series’ curator, Brendan Sexton, as a chance to take a step back from the technical and simply “get lost in the material”. Meredith Bowles of Mole Architects used his projects to demonstrate how timber can be celebrated even within the constraints of a simplified ‘kit-of-parts’ approach.

Mole design entry for Coton Visitor Centre

The incremental increase in size of timber trusses over Mole Architects’ shortlisted design for Coton Visitors Centre makes for a roof of expressive grandeur. The practice’s design for the Cambridge Department  of Architecture studio extension warranted visualization of the build process through the eyes of the contractor: timber elements were assigned as a series of primary, secondary and tertiary pieces in kit of parts.

Mole studio extension

Following on from this Simon Smith pondered, in the context of the UK’s limited timber resources, how can we do more with less? He captured the great capabilities of timber design through the novelty of hardwood timber bike frames. At the other end of the scale, he noted the material is finding its way into the corporate environment, having been chosen for AHMM’s plans for the new Google headquarters in Kings Cross. Simon’s practice, Smith  and Wallwork, is currently working with Cullinan Studio on developing a prefabricated panel system for a modularised school building at St Joseph's Catholic School in Swindon. Simon suggested that much of the system could be locally sourced from UK timber – a building “grown in Britain”. Still, although the decking could all be sourced from Norbord UK, the softwood flanges would have to be sourced from Germany where larger timbers are available.

Cambridge University students' bridge designs

Smith and Wallwork have already engaged in extreme local sourcing designing a small bridge over a ditch for the Woodland Trust in Cow Hollow Wood, Cambridgeshire. Having involved students from Cambridge University in the design project, Simon, lecturer Michael Ramage and PhD student Patrick Fleming came up with the idea of planting a living willow bridge.

Willow stress testing

A lack of structural precedents for willow weaving meant real innovation, with calculations and stress testing performed from scratch. Having planted the main willow members on each side of the crossing point, coppiced white willow of 40-50mm diameter was woven to form the bridges arch and deck.

Despite the late spring the willow has started sprouting in the last month, officiating the bridge as a true living timber structure.

Later Ted Cullinan presented his series of Olivetti offices in the 1970s, which also demonstrated how timber can be used in order to animate a structure, albeit less literally than a living bridge. Situated across the North in Carlisle, Belfast, Derby and Dundee, featured playful systems of plywood fins and trusses, with easily divisible adaptable panels. The event’s chair, Roddy Langmuir of Cullinan Studio, noted that back then Ted designed with plywood almost as CLT systems are designed today.

Construction of the Olivetti offices

Jumping forward ten years, Ted poetically described how timber leased new life into St Mary's in Barnes, a 12^th century church that had previously endured fire. Based on the existing roof arch, new timber trusses were designed to grow out from the burnt original, harmonising with the existing structure.

St Mary's Church, Barnes

Ted sketches St Mary's as he talks

Ted then showed how the process of building in timber was celebrated at the Hooke Park lodge designed with Buro Happold. Forest thinnings were curved into arcs by being weighed down with barrels, bound together, pulled down, clad and turfed.

Green timber thinnings weighed down with barrels

Hooke Park lodge

Ted noted the trend of designing in wood becoming bulkier in order to reduce the number of joints, resulting in the prevalence of CLT over frame structures. There is a worry that systems such as CLT might mean a loss of valuable carpentry skills. This accords with the critique of current culture quoted by Simon, that there is a tendency toward "substitution of more material for less labour". Nurturing the next generation craftsmen is vital. Equally crucial is better timber education for the insurers of today and tomorrow; the event’s discussion acknowledged that insurance issues of fire risks as well as any procurement limits need a lot more work.

Studio in the Woods

However at the crux of the projects presented, was the importance of educating a new generation of timber designers. Indeed timber jointing and detailing often takes more design effort than masonry or concrete. Meredith highlighted this with his involvement in Studio in the Woods, a course for young architects and students that enables hands on experience in designing and building in timber. Such experience allows for a better understanding of fixing design, which when mastered allows the simplicity of the material to shine through.

Roddy surmised that British timber ingenuity could be a result of its relative scarcity in the country. Designers such as Meredith, Simon and Ted, have had to innovate with the material to ensure is goes further, showing that perhaps it is the designers and not the timber that should be grown in Britain.

Further reading: The State of the WorldsForest 2012 report